Myself, writing for 9to5Google:
We’ve heard about a few Enterprise Edition prototypes since the beginning of the year, but there are a couple slightly different iterations of the device that are now being more widely tested. Google is introducing a larger prism that extends further, allowing the user to more comfortably look directly up rather than feeling the need to look up and to the right. The Explorer Edition was infamous for eye strain problems after prolonged use, and this change was likely made with that in mind.
Larger prism, Intel Atom, external battery packs. The last is perhaps the most interesting. Battery packs are definitely needed for the many enterprise solutions that have been built for Glass.